The invention relates to a process and to a particular arrangement of elements for electrical discharge machining an electrode workpiece by way of an electrode tool.
The metal or metal alloys of which the active surface coating of an electrode tool is made has an important effect upon the machining efficiency of an EDM apparatus and the rate of wear of the electrode tool. It has been discovered that some metals having a low vaporization temperature, that is being relatively easy to electro-erode by EDM, are provided with the particular property of facilitating the triggering of electrical discharges, apparently in view of the fact that such metals load the dielectric machining fluid with particles of very small dimensions which play an important part in ionizing the machining fluid and triggering the electrical discharges in the machining gap between the electrode tool and the electrode workpiece.
Due to the presence of such metallic particles in suspension in the machining fluid, machining is effected under improved stability as soon as the electrical discharges are triggered, and it is possible to increase the gap between the electrodes, which in turn results in improving the cooling of the electrode surfaces at the machining zone, and thus in increasing the machining, or material removal, rate.